1. Field of the Invention
This invention relates generally to an electrical signal management system. More specifically, the present invention relates to an integrated system for electrical signal switching and amplifying. Also, the present invention relates to an automatic calibration system for calibrating the electrical signal switching and amplifying hardware in the integrated system.
2. Prior Art
Electrophysiology signal amplification systems commonly include a switch box generally located at a patient's bedside during an electrophysiology procedure. The switch box receives the proximal ends of intracardiac catheter leads, ECG leads, blood pressure sensor leads, breathing sensor leads, temperature sensor leads, pulse sensor leads, or the like. The leads are input by attaching them to input terminals which are arranged on the switch box in a grid-type fashion and labelled for identification either numerically or by color. The switch box outputs to an amplifier which in turn outputs to a computer processing unit, which also in turn may output to a monitor or chart recorder if desired.
During setup of the switch box, the computer processing unit must receive information identifying the input locations of each of the leads in the input terminal grid. This is commonly accomplished by having one operator at the patient's bedside attach the leads in one-by-one fashion into the switch box, and then announce to a second operator the identification of each input terminal label corresponding to the particular lead being inserted. The second operator then simultaneously inputs into the computer processing unit the label indicating the particular parameter being monitored and the corresponding output terminal identification number or color as it announced by the first operator.
After the leads have been attached to the switch box and the computer processing unit has received the necessary labels related to the positioning of the leads and the related input terminal numbers or colors to which the leads correspond, the procedure is commenced. However, very often during an electrophysiology procedure, it is desirable to either move a catheter to a different position in the patient's heart, to add a catheter, or to compare signals received from various catheters. In any of these events, it is necessary to re-identify the particular label given to the catheter lead so that the changes or additions may be properly input into the computer processing unit. Because of the physical separation of the switch box and the computer processing unit, and the necessity of having two operators perform redundant operations to ensure that the computer processing unit correctly correlates the label of the catheter lead with its position in the switch box, necessary changes during a procedure can cause errors in the analysis data to occur, as well as potential injury to the patient.
Attempts have been made to solve the problem of input terminal/lead label correspondence during setup and operational use of signal acquisition and processing systems such as the electrical signal management system of the present invention, with varying success. For example, U.S. Pat. No. 4,037,586 to Grichnick, describes an electroencephalograph which includes a visual display panel which is actuated in response to digital signals for indicating the particular pattern in which electrodes connected to the patient are processed to provided desired output signals. Although this invention may help an operator view the particular processing order of signals received by the device, it nevertheless fails to assist the physician in setup of the device for operation or in changing the setup during a procedure.
U.S. Pat. No. 4,695,955 issued to Faisandier, describes a prior art electronic device which acquires and processes signals originating from sensors attached to a patient. The device automatically recognizes a sensor lead attached to an input terminal thereof due to the mechanical design of the lead itself, and automatically programs the processing system thereof for the proper signal amplification, energization, and processing elements. This device simplifies setup of a procedure by automatically recognizing the particular lead attached to the input terminal. It nevertheless contains the drawback of requiring the use of leads which can be mechanically identified by the device to initiate automatic programming of the processing system. Further, the device fails to allow relabelling of a lead depending on a change in the corresponding sensors position on the patient, and/or a change in the particular parameter being monitored by the sensor.